I don’t mean to suggest that doing your utmost to foster a culture it would be good to grow up in is the rational choice in the game-theory sense; the expected probability of success is far too low for that. Nor would I see it merely as a moral obligation that you incur when you bring children into existence. It’s more direct than that. When you look down at your wide-eyed little one squirming in your arms and your mind turns to the idea of her doing the same with her own little one, the generations coming and going like leaves on a tree, striving to improve society seems no more optional than changing a diaper in the middle of the night—to be vulnerable to the fate of your child just is to be vulnerable to the fate of your society. The only real question is how to help.